As a novel display device, Organic Light-emitting Diode (OLED) display device has the advantages of good color saturation and wide angle of view. However, luminescent and function materials within the display device are sensitive to moisture and oxygen, where the parameter requirements for moisture resistance and oxygen resistance of the corresponding products are in that: permeability of oxygen is required to be less than 10−3 cc/m2/day and permeability of moisture is required to be less than 10−6 g/m2/day. Currently, OLED display devices in middle or small size are packaged by means of printing frit.
As shown in FIG. 1, packaging by means of printing frit includes the following steps: placing first a mother substrate 20 to be packaged on a vacuum adsorption platform 10 of a vacuum adsorption system, and then adsorbing, by vacuumizing, the mother substrate 20 to be packaged to fix it on the vacuum adsorption platform 10; subsequently, placing an alignment substrate (Mask substrate, not shown in FIG. 1), which is used for determining positions of frit, on the mother substrate 20 to be packaged, and then printing the frit to the mother substrate 20 to be packaged along grooves of the alignment substrate; finally, removing the alignment substrate and packaging another mother substrate with the mother substrate 20 to be packaged, so as to form a package assembly. It should be noted that, a plurality of grooves, which may be in a rectangular ring shape, are provided on the alignment substrate, and area on the mother substrate 20 to be packaged may be divided into a plurality of display areas 22, a plurality of packaging areas 21 and a plurality of cutting areas 23, wherein the size, shape and position of each of the grooves on the alignment substrate correspond to those of a packaging area 21 on the mother substrate 20 to be packaged and thus the packaging area 21 may be in a rectangular ring shape as well, as shown in FIG. 1. The area surrounded by one packaging area 21 is one display area 22, and the areas between adjacent packaging areas 21 are the cutting areas 23, wherein a plurality of display panels can be formed by cutting the package assembly that has been packaged along the cutting areas 23.
The inventors have found that at least the following problems exist in the prior art. Most of vacuum adsorption systems used in the prior art adopt grooves or adsorption holes on the vacuum adsorption platforms. A common disadvantage to these two types of vacuum adsorption platforms is that positions on the mother substrate to be packaged (i.e., the packaging areas on the mother substrate to be packaged) on the vacuum adsorption platform corresponding to the grooves on the alignment substrate will be deformed due to action of the adsorption force from the vacuum adsorption platform, which in turn causes large step on the surface of the printed frit, so that poor packaging due to untightness may occur when packaging the mother substrate to be packaged with another mother substrate and thus the service life of the display device will be affected.